SMIL is a layout and presentation language used on mobile phones that allows display of media. A set of media items can be played together. This is similar to a slide on a presentation or a slideshow. Each “par” SMIL tag specifies that the media are grouped and displayed or played in parallel. There are certain constraints or rules, because of receiving device limitations, that specify which types of media items can be placed on the same “slide.” Media Content type tags may for example include (a) text, (b) image, (c) audio, and (d) video.
The following is an example of a SMIL presentation layout under the “head” tag. The media is given under the “body” tags along with how long to display them e.g. dur=“5s” means to display for 5 seconds. This example has 2 “par” tags which can be thought of as 2 slides that are played in order. The first slide has text, an image, and an audio data. The second slide has only 1 image.
<smil> <head>  <layout>   <root-layout width=“40” height=“40”/>    <region id=“REGION_1” left=“0%”    top=“0%” height=“67%” width=“100%” fit=“meet”/>    <region id=“REGION_2” left=“0%”    top=“67%” height=“33%” width=“100%” fit=“meet”/>  </layout> </head>  <body>   <par dur=“5s”>    <text src=“smiltextpartfilename0.txt” type=“text/plain”    region=“REGION_2”/>    <img src=“08-25-04_1443.jpg” type=“image/jpeg”    region=“REGION_1”/>    <audio src=“smil_vn_1093446932.amr”/>  </par>  <par dur=“5s”>    <img src=“08-24-04_1213.jpg” type=“image/jpeg”    region=“REGION_1”/>   </par> </body></smil>
In general, the SMIL presentation layout is generated by the handset sending the data, or by a content provider.